Studies of North American Bees 75 



Allotype. — Ute creek, Costilla county, Colorado, 9,000 feet, 

 June 28, 1907 (H. S. Smith), J^. 



The male of alpha is exceedingly close to A^. elrodi (^, but 

 differs in the shorter lateral face marks which come to an acute 

 point above (broader and more or less truncate above in elrodi), 

 the lack of a postorbital stripe (always a yellow stripe on 

 posterior orbits below in elrodi) and the black apical margins of 

 tergites 1-6 and sternites 2-6 (these usually reddish or suffused 

 with that color in elrodi). The small size and hairy clypeus 

 easily separates it from crazvfordi J*. The . restricted yellow 

 areas on the face and the short lateral marks distinguish it at 

 a glance from obliterata J*. From A'', fragilis Cresson, it may be 

 separated by the longer third antennal joint and non-denticulate 

 flagellum. In Cockerell's table of Rocky mountain species it 

 runs to N. paUidclla Ckll., but that species seems to be a Nomada 

 sens. str. allied to taraxacella, modocoriim and subangusta, and 

 alpha differs from it in the brighter yellow maculations, tergite 

 I without red and its band complete, bands on 4 and 5 not enclos- 

 ing a dark spot, venter black with yellow bands attaining the 

 lateral margins of the sternites, less black on the first four 

 femora, hair of mesoscutum white, redder nervures and different 

 venation, and face broader than long. 



Nomada (Heminomada) laramiensis 11. sp. 



3. Length 8 mm. Black ; clypeus, lateral face marks extending broadly 

 up orbits to level of insertion of antennae and there terminating broadly, 

 line under eye, posterior orbits extending two-thirds of the distance to 

 summit, mandibles except tips, labrum, scape in front, collar, tubercles, 

 tegulae, large L-shaped spots on mesopleura anteriorly, large spots on 

 lobes of mesoscutellum, spots on legs, and abdominal bands, bright yel- 

 low. Head and thorax coarsely and closely punctured, abdomen very 

 minutely and feebly punctured. Clypeus, supraclypeus, and sides of face 

 directly beneath the insertion of antennae densely covered with appressed 

 silvery sericeous hair, similar to that of N. elrodi but much denser; ver- 

 tex, cheeks and most of thorax copiously provided with erect pale hair, 

 that on vertex, mesoscutum, mesoscutellum and metanotum distinctly tinged 

 with ochreous, that on cheeks, pleura and propodeum gray, becoming 

 silvery on the pectus. Scape somewhat swollen, bright yellow with a black 

 line behind, flagellum bright red with the five basal joints black-spotted 

 above, antennal joints 3 a shade over one-half as long as 4, due to the 



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